Physical Review A

Formation and detection of ultracold ground-state polar molecules

Christopher Haimberger, Jan Kleinert, Mishkatul Bhattacharya, N. P. Bigelow

Published Aug 27, 2004• 159 citations

Abstract

We report on the formation of translationally cold $\mathrm{NaCs}$ molecules starting from a laser-cooled atomic vapor of $\mathrm{Na}$ and $\mathrm{Cs}$ atoms. Colliding atoms are transferred into bound molecular states in a two-step photoactivated process in which the atoms are first photoassociated by trap photons into an excited state molecular complex and then allowed to decay into a bound molecular ground state. Time-of-flight measurements show a translational temperature $T=260\ifmmode\pm\else\textpm\fi{}130\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}$ that reflects the measured temperature of the initial atomic gas.

DOI: 10.1103/physreva.70.021402

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Physical Review A

Formation and detection of ultracold ground-state polar molecules

Christopher Haimberger, Jan Kleinert, Mishkatul Bhattacharya, N. P. Bigelow

Published Aug 27, 2004• 159 citations

Publisher

Abstract

We report on the formation of translationally cold

\mathrm{NaCs}

molecules starting from a laser-cooled atomic vapor of

\mathrm{Na}

and

\mathrm{Cs}

atoms. Colliding atoms are transferred into bound molecular states in a two-step photoactivated process in which the atoms are first photoassociated by trap photons into an excited state molecular complex and then allowed to decay into a bound molecular ground state. Time-of-flight measurements show a translational temperature

T=260\ifmmode\pm\else\textpm\fi{}130\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}

that reflects the measured temperature of the initial atomic gas.

DOI: 10.1103/physreva.70.021402

Related papers

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We report on the formation of translationally cold Cs2 ground-state molecules through photoassociation of laser-cooled cesium atoms in a magneto-optical trap. The cold molecules are obtained after spontaneous decay of photoassociated molecules, and detected after pulsed-laser photoionization into Cs2+ ions. Photoassociation spectra of cesium attractive molecular states below the 6S1/2+6P3/2 dissociation limits are reported, obtained with both ion detection and trap-loss method. A temperature as low as 20−5+15 has been measured for the molecular cloud.We report on the formation of translationally cold Cs2 ground-state molecules through photoassociation of laser-cooled cesium atoms in a magneto-optical trap. The cold molecules are obtained after spontaneous decay of photoassociated molecules, and detected after pulsed-laser photoionization into Cs2+ ions. Photoassociation spectra of cesium attractive molecular states below the 6S1/2+6P3/2 dissociation limits are reported, obtained with both ion detection and trap-loss method. A temperature as low as 20−5+15 has been measured for the molecular cloud.

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We have produced ultracold polar RbCs molecules via photoassociation starting from laser-cooled 85 Rb and 133 Cs atoms in a dual-species, forced dark magneto-optical trap. The formed electronically excited RbCs* molecules correlated to the Rb(5S 1/2 ) + Cs(6P 1/2 ) dissociation limit are observed by trap loss spectroscopy. Following the decay of these excited RbCs* molecules, the formed ground state molecules are directly ionized by a two-photon single-color pulse dye laser, which is a new ionization mechanism for ground state RbCs molecules and thence detected by time-of-flight mass spectroscopy.We have produced ultracold polar RbCs molecules via photoassociation starting from laser-cooled 85 Rb and 133 Cs atoms in a dual-species, forced dark magneto-optical trap. The formed electronically excited RbCs* molecules correlated to the Rb(5S 1/2 ) + Cs(6P 1/2 ) dissociation limit are observed by trap loss spectroscopy. Following the decay of these excited RbCs* molecules, the formed ground state molecules are directly ionized by a two-photon single-color pulse dye laser, which is a new ionization mechanism for ground state RbCs molecules and thence detected by time-of-flight mass spectroscopy.

Chinese Physics LettersAug 1, 20118 citations

Production of NaCa+ molecular ions in the ground state from cold atom-ion mixtures by photoassociation via an intermediate state

Marko Gacesa, John A. Jr. Montgomery, H. H. Michels +1 more

We present a theoretical analysis of optical pathways for formation of cold ground-state ${(\mathrm{NaCa})}^{+}$ molecular ions via an intermediate state. The formation schemes are based on ab initio potential energy curves and transition dipole moments calculated using effective-core-potential methods of quantum chemistry. In the proposed approach, starting from a mixture of cold trapped ${\mathrm{Ca}}^{+}$ ions immersed into an ultracold gas of Na atoms, ${(\mathrm{NaCa})}^{+}$ molecular ions are photoassociated in the excited $E^{1}\mathrm{\ensuremath{\Sigma}}^{+}$ electronic state and allowed to spontaneously decay either to the ground electronic state or an intermediate state from which the population is transferred to the ground state via an additional optical excitation. By analyzing all possible pathways, we find that the efficiency of a two-photon scheme, via either the $B^{1}\mathrm{\ensuremath{\Sigma}}^{+}$ or $C^{1}\mathrm{\ensuremath{\Sigma}}^{+}$ potential, is sufficient to produce significant quantities of ground-state ${(\mathrm{NaCa})}^{+}$ molecular ions. A single-step process results in lower formation rates that would require either a high-density sample or a very intense photoassociation laser to be viable.We present a theoretical analysis of optical pathways for formation of cold ground-state ${(\mathrm{NaCa})}^{+}$ molecular ions via an intermediate state. The formation schemes are based on ab initio potential energy curves and transition dipole moments calculated using effective-core-potential methods of quantum chemistry. In the proposed approach, starting from a mixture of cold trapped ${\mathrm{Ca}}^{+}$ ions immersed into an ultracold gas of Na atoms, ${(\mathrm{NaCa})}^{+}$ molecular ions are photoassociated in the excited $E^{1}\mathrm{\ensuremath{\Sigma}}^{+}$ electronic state and allowed to spontaneously decay either to the ground electronic state or an intermediate state from which the population is transferred to the ground state via an additional optical excitation. By analyzing all possible pathways, we find that the efficiency of a two-photon scheme, via either the $B^{1}\mathrm{\ensuremath{\Sigma}}^{+}$ or $C^{1}\mathrm{\ensuremath{\Sigma}}^{+}$ potential, is sufficient to produce significant quantities of ground-state ${(\mathrm{NaCa})}^{+}$ molecular ions. A single-step process results in lower formation rates that would require either a high-density sample or a very intense photoassociation laser to be viable.

arXiv:1603.08032Physical Review AJul 11, 201625 citations

We report on the formation of translationally cold

\mathrm{NaCs}

molecules starting from a laser-cooled atomic vapor of

\mathrm{Na}

and

\mathrm{Cs}

T=260\ifmmode\pm\else\textpm\fi{}130\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{K}

that reflects the measured temperature of the initial atomic gas.

We have performed photoassociative spectroscopy of cold Cs atoms in a vapor-cell magneto-optical trap, within $10{\mathrm{cm}}^{\ensuremath{-}1}$ below the dissociation limit

6s^{2}S_{1/2}+6p^{2}P_{3/2}

. Our detection method is based on pulsed-laser photoionization of

{\mathrm{Cs}}_{2}

molecules, selectively detected through a time-of-flight mass spectrometer. Temporal and spatial analysis of

{\mathrm{Cs}}_{2}^{+}

ions show for the first time the formation of translationally cold

{\mathrm{Cs}}_{2}

triplet ground state molecules, at a temperature $T\ensuremath{\sim}300\ensuremath{\mu}\mathrm{K}$.

We present a theoretical analysis of optical pathways for formation of cold ground-state

{(\mathrm{NaCa})}^{+}

molecular ions via an intermediate state. The formation schemes are based on ab initio potential energy curves and transition dipole moments calculated using effective-core-potential methods of quantum chemistry. In the proposed approach, starting from a mixture of cold trapped

{\mathrm{Ca}}^{+}

ions immersed into an ultracold gas of Na atoms,

{(\mathrm{NaCa})}^{+}

molecular ions are photoassociated in the excited $E^{1}\mathrm{\ensuremath{\Sigma}}^{+}$ electronic state and allowed to spontaneously decay either to the ground electronic state or an intermediate state from which the population is transferred to the ground state via an additional optical excitation. By analyzing all possible pathways, we find that the efficiency of a two-photon scheme, via either the $B^{1}\mathrm{\ensuremath{\Sigma}}^{+}$ or $C^{1}\mathrm{\ensuremath{\Sigma}}^{+}$ potential, is sufficient to produce significant quantities of ground-state

{(\mathrm{NaCa})}^{+}

molecular ions. A single-step process results in lower formation rates that would require either a high-density sample or a very intense photoassociation laser to be viable.